Coronary artery disease (CAD) and peripheral artery disease (PAD) are conditions characterized by insufficient blood flow, usually secondary to atherosclerosis. Symptoms of ischemia (angina pectoris for CAD or intermittent claudication for PAD) are brought on by stress and relieved by rest. In CAD, symptoms may become life threatening due to myocardial infarction, arrhythmia, and progressive heart failure. In PAD, symptoms are less likely to be life threatening except when critical limb ischemia develops, but the risk of adverse cardiovascular events and death is increased.
Identification and management of risk factors are important in the medical management of both CAD and PAD. Pharmacologic management of risk factors may include anti-hypertensives, lipid-lowering agents, and hypoglycemic agents; smoking cessation, diet, and exercise are often prescribed with variable compliance. Pharmacologic management aimed at reduction of symptoms of ischemia often includes vasodilators, anti-anginal, and anti-platelet therapy. Mechanical revascularization by percutaneous angioplasty (with or without a stent) and direct surgical reconstruction improve blood flow and reduce symptoms. However, restenosis after angioplasty and progression of disease may limit the duration of the benefit.
PAD afflicts approximately 11 million patients in the United States. Approximately one third of these patients experience intermittent claudication (discomfort, pain, fatigue, or heaviness in the leg muscles that consistently is brought on by the same amount of muscular activity and relieved by rest). Claudication is similar to angina and represents ischemic muscle pain that may be localized to the hip, buttock, thigh, or calf. It occurs predictably with the same amount of physical stress. Atherosclerosis is systemic, but often one lower limb is more affected than the other. Patients may develop critical limb ischemia, with rest pain, non-healing ulcers, and/or gangrene. Rest pain occurs when blood supply is inadequate to meet the basic nutritional requirements at rest and typically localizes in the toes or foot of the affected limb.
The prevalence of CAD and PAD is expected to increase in countries with aging populations, as aging is a primary risk factor for atherosclerosis. Less invasive catheter-based treatment methods and more cost-effective programs and treatment methodologies are needed to manage these conditions.